Computing devices, such as personal computers, server computers, and mobile devices, often communicate with one another across networks using the transmission control protocol (TCP), or TCP/IP, TCP is designed to provide a reliable manner for sending and receiving data across a network, and it may be used by web browsers when connecting to the World Wide Web and to deliver email and other files from one computer to another. While computing devices may support multiple TCP connections, too many connections may overload available system resources and/or cause performance issues. To reduce the likelihood of overloading and to increase the quality and availability of additional TCP connections, computing devices may close TCP connections that are not actively being used.